Electromagnetic impulse clock



May 7, 1935. J. FINK K 2,000,585

ELECTROMAGNETI C `IMPULSE CLOCK Filed Aug. 23, 1932 wlmi i "l ya Il l,

Patented May 7, 1935 PATENT OFFICE ELECTBOMAGNETIC CLOCK `Josu Fink.Waltham, Mass... assigner' to Waltham 'Watch Company, Waltham, Mass., acor-Peration of Massachusetts matin!! m 23. 1932, Serial No. 630,028

i This .iuvmtlon nelaias'to Atime pieces oct they *die in a drivingspring is periodically rcwound ,by magnetic effected iby c1csi112 :thecircuit of .an destro-magnet whenever a, predetermined proportion di theenergy of the sprint has been enpemled. 4The object ofmeinnentienhssheen-tofurmshaclodrof this character possessingthecapability of long lite with `minimum deterioration thmngh manyopelhns o! its :circuit controlling switch, and thenatnre of which lendsitself to design in a Ime variety of different sizes and capacity foroperation by currents of widely varying volt.- sits. That is, moresneciflcalhr, my aim has been to provide s clock suitable for use inauto# mobiles. 5er instance, operable by the low volt,- axe current ofthe storage battery such an automobile. and capable o functioningwithout derwssment nots/i the shocks and vibrations yto which ,it issubjected when carried by sn automobile; :whiierisie same design. withappropriate variations. may be embodied in mantel or v@weil vnud thelike, operable by metric lighting currents and oliver currentscrflcomperahly hizh. or hicher.\vol1tages. whether direct oralternating. Another object hmbeen to furnish a clock which, with sinin-r inmm cf change. may be connected in either an lulated electricycircuit or in a grounded While `primarily designed tor paroisses abovestated, the principles and essentials of thefwinventiqn are notlimitedto use in a chock only, but are adapted for driving other Ehe newcharacteristics .of .the invention .include. among .other things, the`use of an encuedimvity switch 4morvcfhle angularly by and with thearmature of an eleetromagnct, the use o! thesnme spring to serve both asa. leading in conductor for the switch and as -the main driv ing springof the time pieee,'and`means including replaceable switch carriers foradapting the sometime' piecev for use either in an vinsulated circuit oraygrounded ch'cuit.

In the drawing.-

Fig. 1 is a rear elevation of the time piece showing r partielderly vtheelectrical equipment;

2 is a horizontal section online 2.--2 of F11. l;

43 is .a partial rear elevation and partial Sectouon line 3-3 0I Figa; v

Fis. 4 is assction en linoM-f-G of Eig. `2;

Fis -5 is s Section amlrear elevation on the plane of line 5-5 of Fig.2, shown on an enlarged scale;

Fig. 6 is a cross section on lined-6 of Fig. 5;

Fig. 'l is an elevation and partial section o! the switch carrier shownin Figs. 1 and 2";

Fig. 8 is a cross section of the same taken on line 8 8 of Fig. "7;

Fig. 9 is a view similarto Fig. l showing the arrangement of ytheapparatus adapted for use in a grounded electrical circuit;

Figs. 10 and 11 are sectional views of the switch carrier taken on lineIII-I0 and II-H' respectively of Fig. 9;

Fig. 12 is a perspective view of the associated disk and pinion whichdrives the clockr train through 4'the medium of a coupling spring;

Fig. 13 is an elevation of the coupling spring and the ratchet Wheelwhich applies tension thereto under impulsion by the main spring.

Fig. 14 is a view similar to Fig. 9 showingan added means for obtainingquick closing and openingof the switch;

Fig. 15 is a similar view ofthe switch showing it in open .circuitposition;

Fig. '16 is an .elevation of the connector .he-k tween the switchcarrier of Fig. 14 and the stai! of the amature.

Like reference characters designate the 4same parts wherever they occurin all .the figures.

The `electrical and magnetic equipment of my improved clock `comprisesan electromagnet having pole kpieces 1II and I2, a wire coil I1, enarmature i4, a svntch carrier I6, and a, gravity switch I6. The polepieces are secured to s. holder plate I1 by posts Ill, Il, and 19,18,:to which nuts are applied. A vlaminated core 20 passing through themagnet coil or winding is secured by the .posts IB, I8 and the nutsthereon. A bridge y2I of non-magnetic material passes across the gapbetween the magnet poles at the opposite .side of thelatter from theplate l1, being positioned by the posts I9,` I9, and lsecured by nuts onyseid posts. This bridge :md `the plate lI1 rprovide 'bearings for astaff 22 .to which the armature il is secured. Said staff also protrudesbeyond the bridge and supports :the switch .carrier I5.

Preferably the magnet pol have concave faces opposite to each other andvcquidistsnt from the stadi 22, and the amature is s. massive be.:`having .a length .nearly yas great as the .distance between these.opposed faces, so that it may rotate between them with .a air gan, hut.has .a substantially less width.`

The .switch carrier I5 is a block of insulating ture, and from eachother.

magnet.

material preferably, although not necessarily, of cylindrical shape andof substantially the same diameter as the longer dimension of thearmature. It may, however, be of any size and shape which enables it tooccupy, and freely rotate in, the area between the coil I3, posts I9,I9, and the nearer part of the circumference of plate I1. It is securedto the staff 22 by a set screw 23 threaded through the base of a thimble24 which is embedded in one side of the carrier.

The switch I9 in this embodiment is a mercury switch consisting of aglass tube containing a globule 25 of mercury, and in one end of whichare sealed the ends of wires 2B and 21 which constitute the terminals ofthe switch. This tube is sunk into the carrier I5 from the end facethereof at one side of the pivot axis or staff and with its longerdimension tangential to an arc concentric with such axis so that, whenthe carrier is mounted with its axis horizontal, and is rotated, themercury globule will roll or flow by gravity from one end to the otherof the tube.

With the clock organized for connection in an insulated electriccircuit, two spiral springs 23 and 29 are provided, secured respectivelyto posts 38 and 3| which are mounted on the plate I1 and projectrearwardly therefrom. The posts may be insulated from the plate, or thesprings insulated from the posts by any suitable means known in the art;the important fact is that both are insulated from the plate and otherconductive parts of the clock struc- Spring 28 extends across the backor outer side of the switch carrier and is connected with a pin 32 whichin turn is connected with the switch terminal 26 by a conductor 33.Spring 29 crosses the inner or front side of the switch carrier and isconnected with a pin 34 which in turn is coupled electrically by aconductor 35 (Fig. 2) with the switch terminal 21. These pins aremounted in the switch carrier in any manner suitable to Yhold them withthe rigidity necessary for performing their mechanical functions laterdescribed; and the conductors 33 and 35 are led to them from the switchterminals in any convenient manner, preferably being led and embedded inchannels cut or pierced in the substance of the carrier. As thissubstance is of insulating material (at least as to that part of thecarrier which holds the pins and conductors), the two pins and theirconductors are insulated from each other.

One of the springs, as 29, is connected by a conductor 36 with oneterminal of the magnet coil. The other spring and the other terminal ofthe coil are connected by conductors 31 and 38 to the opposite sides ofa source of current, here represented conventionally as a battery 39.

The springs 28 and 29 are designed to serve also as main springs fordriving the clock movement. They are therefore coiled in a spiral ofseveral convolutions and are made of a substance, size and mass suitablefor this purpose as well as for the ypurpose of carrying whatevercurrent rnay be needed to energize the Alloys of copper, classed asbronzes, are known in the art which have ample hardness and resilience,as well as conductivity, for these purposes; springs of such an alloy.However, steel may be "used provided the springs are made with sufand Iprefer to make these cient sectional area to carry the current. They arealso put under tension, or partially wound up before the clock is putinto service; which may be done by rotating the holder I5 on the staffbefore the set screw 23 is tightened up to clamp it. When set up readyfor service, the parts are so placed that the springs exert tensioncounterclockwise on the armature I4, tending to hold it in a positioncrosswise of the lines of magnetic force, where it is arrested by a. pin44, which is carried by the armature, engaging one end of an arcuateslot in the plate I1; and the switch is then in the position shown inFig. l with its end which contains the terminal contacts enough'lowerthan its other end to insure location of the mercury globule in that endand in contact with the switch terminals.

To equip the clock for grounded circuit use, the spring 28 is removedand the switch contact 26 is grounded on the framework. This change maybe most easily made by substituting for the switch holder I5, anequivalent switch holder I5a which is identical with it except in thatthe contact 21 is coupled by a conductor 46 with the metal socket 24wherein set screw 23 is seated; and the circuit connection is continuedthrough such set screw and the staff 22 to the frame of the clock. Thecontact 26 is connected by conductor 33 with pin 34a which projects fromthe forward side of the switch carrier for connection with spring 29 andpasses through the substance of the carrier far enough for connectionwith said conductor. This arrangement is particularly suited to clocksdesigned for use in automobiles, where the frame of the clock movement,and one pole of the storage battery, are grounded on the frame of theautomobile, the other pole of the battery being coupled by an insulatedconductor with the magnet coil I3, and the latter and spring 29 beingalso insulated from the frame. The clock movement consists of the usualgear train and balance escapement, the members of which are mountedbetween a pillar or front plate 41 and a back plate 48, and/or a bridgeor bridges of any suitable design. That is, the clock movement may belike any spring driven movement, or of any other suitable design, exceptthat the usual main spring of such clock is omitted. Energy for drivingthe movement is furnished by the springs 28 and 29, or the single spring29 when only one is used, transmitted from the armature I4 by the pin44, previously mentioned, which projects through the slot 45 (which isconcentric with staff 22) in the plate I1, and a registered slot inplate 48 to connection with a driving member 49 for the clock movement.This connection is a permanent one Such driving member is here made as adisk rotatable about a staff 50 mounted in the plates 41 and 48 inalinement with staff 22. It drives through a one-way clutch consistingof a ratchet wheel 5I, also rotatable about the same staff, and a pawl52 connected to theldisk by a pivot stud 53 and pressed upon by a spring54, which also is connected to the disk by a screw 55. A coupling spring56 for continuing the driving effort while the mainspring is beingwound, made as a spiral of several convolutions surrounding staff 50, iscontained in a recess in the ratchet Wheel and connected at one endthereto by means of a pin 51, and at the other end to a pin 51a whichprojects into the recess from a disk 58, which is so mounted on thestaff as to overlie said recess. This spring is made of Bucient .lengthto ive the clock for an extended time, for ce half an hour or more, toMold necessity of resetting the clock if the eussent supply should falltemporarily. A pinion il is made fast to stal i0 and drives the conterwheel of the clock time train through midle pinion 6I which turns abouta pivot stud anchored in the plate 4%.

It will now be apparent that when themagnot is enengized, by closing ofthe switch when the annature occupies a position wherein its valordimension is transverse to the magnetic lines of force. the armature isgiven a sudden impulse im clockwise rotation (with respect to thedrawing) which is powerful enough to give it momentum sufllcient tocarry it to the limit of movement imposed by structural parts of thedevice; such movement being in the construction shown nearly Thus theVdriving pawl i2 iscam'ied backward around the rim of ratchet wheel il,which is prevented from turning with it, by a holding pawl 'B2 pivotedto a stud 63 and pressed toward the ratchet by a Aspring 6,4; said pivotstud and spring being secured to plate n Switch holder Ii is turned atthe same time, andassoonastbecirciutisbrokenbythe mercury globulefalling away from the terminal contacts, the magnetic flux ceases,leaving the armature free to be carried by its momentum beyond theposition where it receives the greatest concentration of magnetic linesof force. Atthe same time the springs 28 and 29, or spring il when 2B isomitted. are put kunder increased tension which, together withtheinitial tension, is imply sumcient .to drive the movement. When, inthe course of the rotation imparted by such spring or springs(occurring. in the counter-clockwise direction with respect to thedrawing) the pin 44 nearly reaches the end of slot .45, and the amatureis brought crosswise to the field of the magnet, the switch arrives inposition for completing the circuit; and the 'previous action isrepeated.

It is desirable, when the clock is used in an automobile, to prevent thejoltingand vibration of the automobile from throwing the mercury globuleagainst the terminal contacts prematurely, as it might when the switchhas nearly attained a horizontal position but has not turned far enoughfor the globule to pass by gravity into circuit closing position. Toprevent this I provide an obstruction or baille -65 in the casing of the,switch (which is most conveniently made by lndenting the side of theglass tube when softened by heat) so located and designed as to hinderdisplacement of the globule by jolting, while permitting itsdisplacement by gravity when the switch is in the proper position. Butthis. while a desirable feature, is not essential; and 'it lsunnecessary in connection with a clock provided for use where it is notsubjected to any considerable vibration.

The fact that the switch is mounted off center from its axis ofrevolution is a useful feature, as it causes the momentum of theglobule, imparted by its rapid revolution under the magnetic impulse, tocarry it forcibly away from the terminal contacts and insure opening ofthe circuit when the armature is arrested at the end of its swing. Sucharrest occurs in this design when the pin M brings up against the end ofpaul i2, kbut it may .equally well be caused by the and of slot li.

Al'urthcr means for eectingsudden opening and closing of the circuit,which may be und withv the means just described, or alternativelytheretmis shown yinliigs. 14-16. yIt comprises mounting the switchcarrier with capacity for angular motion independently of the armature.impelling it by the armature with provision :for lost motion, and givingit an increment of angular movement, suddenly applied, when the cinna-`ture nears the end of its swing in each direction.

In the embodiment illustrated, which is applied to the grounded circuitarrangement of the electrical apparatus, the switch carrier li ismounted loosely on the armature staz 22, and a plate or disk 66 ismounted `fixedly on the staff. One of the springs 28 or 29, or its.equivalent, here designated as 28a, is coupled to the plate 66, or tothe staff so as to have the same mechanical functions previouslydescribed. It does not, however, have any electrical function. Two ormore springs may be so used if desired.

The switch carrier is provided with a. M'

which projects into a notch 68 i-n the disk Si, serving as a coupler bywhich the disk propels the switch carrier in both directions, and.providing for an angular lost motion of yany ydesinotl amount. I havefound in practice that anangle traversed when arriving in that position;and

when the switch and armature are near the opposite ylimit of oscillation(Fig. 15) the pull of the spring is at the opposite side of the axis andexerts turning movement in the opposite direction. In the course of therotation .of the armature in either direction the pin 10 crosses thedead point and the direction of turning moment applied by spring 69 vonthe switch carrier is reversed.

The eifect of the spring 28a or its equivalent, like that'of the springs28 and 29, is to rotate the staff in counter-clockwise rotation, turningthe disk 66 from the position shown in Fig. l5 to that shown in Figs. 14and 16, and the disk then impels the switch carrier by the 'boundary 1Iof notch 68 acting on pin 61. This pin, yand also pin 10, are angularlyso related to the switch or circuit closer that when the latter is 4thusbrought to a, horizontal position, or nearly so,

and While the mercury globule is still in the end of the tube remotefrom the terminal contacts, the pin 10 is brought past the dead point,whereupon the spring instantly advances the switch carrier through theVangle of lost emotion', which is made great enough to insure gravity.

displacement of the mercury globule into circuit closing position.Movement of the mercury is also expedited by its momentum and the suddenarrest of the switch carrier when pin 6! brings up against the oppositeboundary 12 of the notch. The disk 66, being then turned in clockwiserotation by the magnet armature, propels the switch carrier yby meansyof the .bounding edge 12 until the pin 10 passes the dead point again,and spring 69 then suddenly gives .the

switchk carrier its incremental angle of lost mo-l tion in the clockwisedirection. Sudden arrest of the switch carrier again occurs when thepin61 reaches the boundary 1l; and the inertia eff.

fects resultingtherefrom are cumulative of those due to arrest of thearmature. Thus closing and opening of the circuit are positivelyinsured, and possibility of any of the mercury remaining in bridgingconnection across the switch terminals is definitely excluded. Themercury is forcibly propelled over any obstacle, such as the balile 65,which may be provided to prevent premature closing of the circuit due tojolting of the clock.

It will be understood that the directions indicated in the foregoingdescription as clockwise and counter-clockwise have reference to thepresent illustration, which shows the electrical equipment in rearelevation, and are not to be confused with the actual direction ofrotation of the hands of the clock with which this motive mechanism isused.

In the arrangement just described the spring 69 forms part of theelectric circuit, being in circuit with the conductor 36 and with pinlll, which in turn is coupled by a conductor 2'3 with one of the switchterminals, the other terminal being connected by a conductor ld with ametal bushing l5 in the switch carrier which surrounds stair 22. Whenused in an insulated or nongrounded circuit, the connection 'i4 is ledto an external contact on the switch carrier with which a stationarybrush in the circuit makes contact. It is to be understood that thespring 69, while strong enough to give the incremental angular movementto the switch carrier herein described, may be much weaker than the mainspring 28a, so as not to aiicct appreciably the functioning of thelatter.

While I have described the member 65 as a disk, it will be understoodthat the outline and angular extent of this member is unimportant,provided only it subtends a large enough angle to provide abutments, asTI and l2, between which an impulse member, as the pin 5l, on the switchcarrier may play with the desired lost motion.

The use of a switch of the closed type is conducive to long life, forits tube or casing is preferably lled with an inert gas, or it may beexhausted to a high degree of vacuum. Thus oxidation is entirely avoidedand sparking largely eliminated. With low voltage currents the sparkingis not serious enough to need any consideration. It can be eliminated,or greatly diminished with currents of any voltage by including acondenser in the circuit. I have not shown such a condenser herein,because its use for that purpose is too well known to requireexplanation.

With suitable selection and design oi the electrical parts, according toprinciples well understood by electricians, clocks may be made accordingto the principles herein disclosed for use with any voltage practicablefor general use, and with either direct or alternating current. Suchclocks, once properly regulated, will run without attention for verylong periods and with only minute consumption of current.

It will be understood that while I have described a mercury switch asthe preferred circuit closer in this combination, I am not limited tomercury as a mobile element of the closer, but may use a ball of solidconductive matter, or a liquid conductor other than mercury. Withincertain aspects of the invention I may also use other types of gravityswitch.

. What I claim and desire to secure by Letters Patent is:

1. In a clock impeller of the character described, an electromagnethaving oppositely disposed poles, an armature rotatably mounted on anaxis midway between said poles and having arms of greater length thanwidth extending oppositely from the axis, a switch carrier secured tothe stan of said armature to be carried and rotated thereby, a spiralspring coiled around the axis of said armature coupled at one end tosaid switch carrier and anchored at its opposite end, and an enclosedmercury switch or circuit breaker mounted on said switch carrier to betilted with rotation of the carrier and having separated terminalcontacts at one end, one of said contacts being in electrical connectionwith the spring.

2. A clock impeller of the character described comprising a rotatablymounted magnet armature, a magnet having poles embracing said armatureand adapted when energized to turn the latter from a position of greaterreluctance to another position of less reluctance with respect to themagnetic field, a switch carrier secured to the staff of said armatureto be rotated thereby, a mercury switch comprising a closed tubecontaining a globule of mercury, closed at both ends, mounted at oneside of said steil with its length dimension tangential and havingseparated terminal contacts in one end, pins projecting from oppositefaces of said switch carrier and each being separately in electrical iconnection with one of said contacts, coil springs on opposite sides ofthe switch carrier surrounding said stail, each mechanically andelectrically connnected at one end to one of said pins and beingmechanically anchored and electrically insulated at the other end, andelectrical connections betwecn said springs and the magnet winding andsource of current respectively.

3. An electro magnetic impulse apparatus comprising an electro magnethaving an oscillative armature, a spring tending to rotate said armatureinto a position of greater than minimum magnetic reluctance, a drivenmember impelled by said spring, a gravity circuit closer in the circuitof the electro magnet, a carrier for said circuit closer rotatable abouta horizontal axis, coupling means having an angular lost motion forrotating the switch carrier from the magnet armature, and means forrotating the switch carrier ahead of said impelling means when itapproaches circuit closing position.

4. In a clock of the character described, a revolubly mounted circuitcloser having a mobile conductive element gravity impelled to circuitclosing or circuit opening position according to the position of thedevice about a substantially horizontal axis, an electromagnet having anarmature mounted rotatably between the magnet poles with capacity forrotation through an angle of the order of means comprising separatedabutments connected for rotation by and with said armature and aprojection from the circuit closer embraced between said abutments withprovision for angular lost motion, a spring acting on the armaturetending to place it in a position of greater than minimum reluctancewith respect to the field of the magnet, and means for suddenlyadvancing the circuit closer into circuit closing position when advancednear to such position by one of said abutments under the impulsion ofsaid spring.

5. The combination with an electromagnet, of

an armature rotatably mounted between the poles of said magnet,yieldable impelling means acting on said armature and tending to returnit to a position of greater than'minimum reluctance with respect to themagnet field from a positien'cf minimum reluctance with respect to suchfield, a member yhaving angularly separated abutments secured tosaid'armature for angular movement by and with the same, a switch having'a 'gravity impelled circuit kclosing element mounted to turn about ahorizontal axis, a projection from said switch located with capacity forvlost motion between said abutments and adapted to be driven by one orthe other of said abutments with rotation of the armature inrespectively opposite directions, a spring coupled with said switchcarrier at a pointeccentric to its axis of revolution so that the lineof its force application is shifted from one side to the other y of theaxis of rotation as the switch carrier is advanced in either directionby one or the other of said abutments.

6. In an electromagnetically impelled clock, the combination of anelectromagnet, a rotatable armature for said magnet, a spring connectedto said armature and tending to place it in a position of greater thanminimum reluctance to the magnetic field, a coupling between saidarmature and the clock movement for driving the latter, a switch carrierrotatably mounted co-axially with said armature and having a mercuryswitch in circuit with the magnet field, the axis of the armature andswitch being horizontal, separated abutments connected and movable withthe armature, a projection from the switch carrier embraced by saidabutments and having capacity for lost motion between them, a springcoupled to said switch carrier to exert force at an eccentric pointthereon toward the axis of the switch, but in a line extending past theaxis on one side and then the other side thereof in the course of thearmature-impelled movement of said carrier.

7. An electromagnetic impulse motor comprising an armature, a switchcarrier, and a driving member, all mounted oscillatively on the sameaxis and mechanically connected together, an electromagnet having polesembracing said armature, and the amature having a greater mass ofmagnetic material in one diameter than Ain any other diameter, anelectric switch comprising an air excluding tube mounted on the switchcarrier containing separated contact terminals in one end and a mobilecircuit closing body adapted to shift into and out of contact with saidterminalsl as the switch carrier is rotated to one position or another,a driving spring coiled around said axis, having a mechanical connectionat one end with the before named oscillative members and a stationaryanchorage at its opposite end and being under tension such that it tendsto place the armature in a position where the diameter which containsthe greatest magnetic mass is transverse to the magnetic eld, a stopco-operating with the spring to establish such position of the armature,the switch being then located with the end which contains said contactterminals lowermost, whereby the mobile body is caused by gravity toclose the gap between them, and the armature being movable undermagnetic impulse from said position through an arc wide enough to tiltthe switch so that the mobile body shifts out of engagement with saidcontact terminals, and a one way clutch operable by the driving memberto transmit motion under the impulsion oi' said spring.

8. An electromagnetic impulse motoras set forth in claim 7 in which saidspring is oi electrically conductive material and is in electricalconnection at one end with the eld winding rof the electromagnet and atits other end with one h of said contact terminals, thefother of saidterminals being otherwise connected in the same circuit.

9. An electromagnetic impulse motor asset forth in vclaim '7 ycomprisingtwo springs supported and arranged substantially as set forth, eachbeing connected at one end separately to one of said contact terminals,and being connected at their opposite ends separately in opposite sidesci an electric circuit, and the iield winding oi the magnet beingconnected in one side oi' the same circuit.

i0. An electromagnetic impulse motor comprising a magnet armature, aswitch carrier and a driving member mounted to oscillate about the sameaxis, the armature and driving member being rigidly connected togetherand the switch carrier being independently oscillatable, connectionsbetween the switch carrier and armature organized to drive the formerpositively in each direction with capacity for a limited degree of lostmotion, a magnet having poles embracing said armature, a springconnected to the armature tending to place the armature in a position ofgreater than minimum reluctance with respect to the magnetic eld and astop coacting therewith for so positioning the armature, the springbeing put under increased stress by movement of the armature effected byexcitation of the magnet, a spring connected to the switch carrier andarranged to hold the latter at one limit of its lost motion when thearmature is in the before mentioned position of reluctance, and to shiftthe carrier to the other limit of its lost motion when the armature isdisplaced by magnetic impulsion, an electric switch carried by saidcarrier comprising a hermetically sealed tube having separated terminalcontacts in one end and a movable circuit closing body, mounted on lsaidcarrier in such position that the movable body is brought against saidcontacts when the armature is in the before named position and theswitch carrier is at the rst of the above named limits of its lostmotion, the movable body being displaced from contact when the armatureand carrier are moved by magnetic action.

11. An electromagnetic impulse motor as set forth in claim l in whichthe switch is mounted eccentrically with respect to the carrier, wherebyits movable circuit closing body is given momentum in the course of thelost movtion of the carrier and the switch tube is arrested suddenly ateach limit of such lost motion.

12. An electromagnetic impulse motor as set forth in claim 10 in whichthe spring for effecting the lost motion movements of the switch carrieris an electrical conductor and is electrically connected with one ofsaid contacts in a circuit which includes the other contact and thewinding of the electromagnet.

13. An electromagnetic motive apparatus comprising an electromagnet, anarmature for said magnet rotatably mounted between the poles thereof andmovable from a position of relatively great reluctance with respect tothe field of the magnet to and through a position of minimum reluctancewhen impelled by magnetic Y iiux, two springs coupled to said armatureand Vfil) both acting to exert torque on the armature in the samedirection, tending to return the armature to the rst named positionafter displacement therefrom, means including a one Way clutch in rigidconnection with said armature for transmitting motion from the armaturewhen the latter is so actuated by said springs, and a gravity circuitcloser having separated terminals each in separate electrical connection10 with one of said springs; the springs being in circuit between itssaid terminals when the ar mature is in and near the first namedposition, and to break the circuit when the armature is in the positionof minimum reluctance.

JEAN FINK.

